Ceramic coated tuyeres or the like



Dec. 25, 1962 w. H. SCHULTZ CERAMIC COATED TUYERES OR THE LIKE 2Sheets-Sheet 2 Filed June 11, 1958 //V VENTOR WILL 1AM H. SCHUL TZAffarnev and (IER

William H This invention relates to a ceramic coated tuyere and isparticularly directed to tuyeres or similar members which are inserteinto a blast furnace. Such members include tuyere coolers, monkeys andmonkey coolers. These members are normally made of copper and aresubjected to extremely severe operating conditions because of the hightemperatures in the furnace, abrasion from the moving furnace burden,and splashes of molten pig iron from the burden falling into the furnacebash. Because of these conditions, the tuyere and other members have arelatively short life.

It is therefore an object of my invention to provide a blast furnacetuyere or the like which has a longer than normal life.

This and other objects will be more apparent when referring to thefollowing specification and attached drawings, in which:

FIGURE 1 is a longitudinal section of a tuyere and tuyere cooler asplaced in a blast furnace wall;

FIGURE 2 is an enlarged sectional view of the tuyere of FIGURE 1;

FIGURE 3 is a sectional view taken on the line Ill-Ill of FIGURE 2; and

FIGURE 4 is a sectional view showing the monkey and monkey cooler in thefurnace wall.

Referring more particularly to the drawings, the reference numeral 2indicates the wall at the bottom of a blast furnace. A tuyere cooler 4which supports a tuyere 6 is supported in the wall 2. The tuyere 6 is ofusual construction having a body 8 with an air passage 10 therethroughfor the admission of a blast of air to the furnace, this passage beingconnected at its inlet end with the source of air supply by means of apipe 12. Surrounding the air passage 10 is a chamber 14 to which acooling fluid is supplied by means of an inlet pipe 16. The fluid afterpassing through the chamber 14 is discharged through a pipe The tuyereand tuyere cooler are preferably made of copper but may be made of acopper alloy. The term copper as used in the claim is meant to includepure copper or an alloy which is predominantly of :1, the materialsbeing those most commonly used in tuyeres. The surface of the tuyereexposed to the burden of the furnace is coated with a metallic layerwith a ceramic coating 22. being applied over the metal coating. 1 havefound that a metal coating having a coefiicicnt of expansion betweenthat of the body of the tuyere and that of the ceramic coating 22 mustbe provided between the body of the tuyere and the ceramic coating toobtain the object of the invention. Metals suitable for the coating 20include austenitic steels such as A131 types 301, 302, 30213, 303, 304,308, 309, 310, 316, 321 and 347, chromium steels such as A151 types 403,405, 406, 410, 414, 420, 430, 431, 440A, 4403, 440C, 442, 443, 446, 501and 502, and pure nickel. The ceramic coating 22 may be of alumina,beryllium oxide, calcium oxide, cerium oxide, chromic oxide, chromite,magnesia, silica, strontium oxide, zirconia, and zirconia oxidesilicate. In applying the coating, the surface of the tuyere to becoated is first roughened, as by grit blasting or knurling, to improvethe adherence of the metal coating. The application of the coating 20 ispreferably done by blowing the metal in powdered form through a flamewhich applies the metal in a semi-molten form to the tuyere, which ispreferably rotated as the powder is applied. The fused ceramic coatingis applied over the metal coating in a similar manner after the metalhas solidified. A similar metal coating 24 may be applied over thatportion of the tuyere cooler 4 exposed to the furnace burden with asimilar ceramic coating 26 applied over the coating 24.

FIGURE 4 shows a cinder notch monkey 28 supported by a cinder notchmonkey cooler 30, which in turn is sup ported by cinder notch cooler 32.The monkey 2d and monkey cooler 30 are made of the same material as thetuyere. A metal coating 34 and ceramic coating 36 are applied over thatportion of the surface of the monkey 28 which is exposed to the furnaceburden. A metal coating 33 and ceramic coating are applied over thatportion of the surface of the monkey cooler 30 which is exposed to thefurnace burden. The coatings 34 and 38 are applied in the same mannerand are of the same material as coating 20 and coatings 36 and 40 areapplied in the same manner and are made of the same material as coating22.

A combination of coatings found to be unite successful is a coating of ametal containing 60 to 62% nickel, 12 to 15% chromium and the remainderiron, manganese and carbon with the ceramic coating being fused alumina(A1 0 The metal coating should be between 0.0005 and 0.02 inch thick andis preferably between 0.002 and 0.007 inch. The ceramic coating shouldbe between 0.001 and 0.04 inch thick and is preferably between 0.005 and0.015 inch.

While several embodiments of my invention are shown and described, itwill be apparent that other adaptations and modifications may be madewithout departing from the scope of the following claim.

I claim:

A structure adapted to be inserted into a furnace or the like comprisinga copper body, a metal coating bonded to and surrounding at least aportion of said body, said metal coating having a thickness between and0.02 inch and a ceramic coating directly bonded to said metal coating,said ceramic coating having a thickness between 0.001 and 0.04 inch,said metal having a coeflicient of expansion intermediate thecoefficient of expansion of said copper and said ceramic and being ofthe class consisting of austenitic steels, chromium steels and nickel,said ceramic being of the class consisting of alumina, beryllium oxide,calcium oxide, cerium oxide, chromic oxide, chromite, magnesia, silica,strontium oxide, zirconia, and zirconia oxide silicate.

References Cited in the file of this patent UNITED STATES EATENTS185,339 Mackey Dec. 12, 1876 639,537 Dickey Dec. 19, 1899 1,161,944Maddy Nov. 30, 1915 2,295,945 Fralish Sept. 15, 1942 2,310,002 Van GeelFeb. 2, 1943 2,340,362 Atlee Feb. 1, 1944 2,377,321 Brown June 5, 19452,470,753 Alban May 24, 1949 2,495,835 Comstock Ian. 31, 1950 2,515,337Clark July 18, 1950 2,696,662 Les Sech Dec. 14, 1954 2,775,531Montgomery Dec. 25, 1956 2,975,078 Rayfield Mar. 14, 1961

